1. Observations of Storms off the West Coast in 2012 from Seafloor Data David Atkinson, UVic Dept. of Geography Steve Mihaly, ONC Dilumie Abeysirigunawardena, ONC Martin Heesemann, ONC 2013 CSAS State of Ocean Workshop February 20, 2013

2. Series of storm events, Jan 19 – 26, 2012: - Synoptic overview - La Perouse traces - ONC Folger Passage (Deep) data: - surface waves - Start with annual variance and comparison, 2011 vs 2012 - BPR power spectra trace, late summer period - spring period close-up - storm period close-up - ADCP currents - storm event response - oxygen - storm event response

3. Series of storm events, Jan 19 – 26, 2012: Synoptic overview. - point to note: potential for different wave source regions during these events

4. January 19 2012 00Z M Typical progression: - “parent” system moves off jet into GoA -Dynamically linked systems generated, moved towards coast and to NE -Support from aloft = rapid increases in strength

5. January 19 2012 06Z 6,4 La Perouse Bank buoy Direction Wspd,Hs M

6. January 19 2012 12Z 10,4 M

7. January 19 2012 18Z 7,3 M 1

8. January 20 2012 00Z 6,2.5 M 1

9. January 20 2012 06Z 11,3 M 1

10. January 20 2012 12Z 15,3 M 1

11. January 20 2012 18Z 15,4 M 1

12. January 21 2012 00Z 16,5 M 1

13. January 21 2012 06Z 960 12,4 M 1 2

14. January 21 2012 12Z 960 11,4 M 1 2

15. January 21 2012 18Z 11,5 M 2

16. January 22 2012 00Z 10,6 M 2

17. January 22 2012 06Z 11,6 M 2

18. January 22 2012 12Z 977 18,6 M 2

19. January 22 2012 18Z 977 20,7 M 2 3

20. January 23 2012 00Z 977 22,9 M 2 3

21. January 23 2012 06Z 10,7 M 2 3

22. January 23 2012 12Z 7,6 M 3 4

23. January 23 2012 18Z 9,4 M 3 4

24. January 24 2012 00Z 10,4 M 4 5

25. January 24 2012 06Z 14,4 M 4 5

26. January 24 2012 12Z 14,6 M 4 5

27. January 24 2012 18Z 13,6 4 5 967 972

28. January 25 2012 00Z 12,5 4 5 964 968

29. January 25 2012 06Z 15,6 4 5 964 968

30. January 25 2012 12Z 10,8 45

31. January 25 2012 18Z 8,8 4 5

32. La Perouse traces

35. Wave height peaks >8m Max sustained wind ~23m/s (gust 30m/s) Note direction shifts

38. ONC Folger Passage (Deep) data : Wave activity expressed as variance

39. log Annual: 2011

40. log Annual: 2011 More energetic, more variable winter season Less energetic/variable summer season

41. log Annual: 2011 February – activity appeared to be winding down - Kicked back in for an active March

42. log Annual: 2012

43. log Annual: 2012 Similar in general form to 2011 – winter active, summer quieter

44. log Annual: 2012 Timings – 2011 winter ended fairly suddenly; 2012 dragged out

45. log Annual: 2012 Timings – both years – late July/August very quiet, September sees increasing activity July/Aug.Sept.

46. First three weeks of September 2012 locally were (very) storm free Observed energy can not be local.

47. Use a running spectral power plot of Folger BPR data to assess wave dispersion - angled tracks between 25s-10s indicate long period waves arriving well before shorter = wave trains pumped out by distant storms Sept 1 2012 Sept 21 2012 Sept 14 2012 Sept 7 2012 Wave Period Relative power

48. log Annual: 2012 Late Jan. Stormy period – most active single week in 2012

49. logspring Spring: 2011 Closer look at variance traces for stormy period JAN 01 FEB 01 MAR 01

50. logspring Spring: 2011 Note pattern – waves often exhibit rapid onset, slow decline - Cordillera blocks eastern progression of storms - move in fast, but stall and die slowly JAN 01 FEB 01 MAR 01

51. logspring Spring: 2011 Note pattern – waves often exhibit rapid onset, slow decline - Cordillera blocks eastern progression of storms - move in fast, but stall and die slowly JAN 01 FEB 01 MAR 01

52. logspring Spring: 2011 Can also observe fairly regular synoptic timing 3 – 7 days between events in mid-latitudes at this time of year JAN 01 FEB 01 MAR 01

53. logspring Spring: 2012 JAN 01 FEB 01 MAR 01 Similar general pattern but a higher level of activity persisted - no February slow-down as in 2012 Storm period

54. logstorms JAN 18 JAN 21 JAN 24 Stormy period: Jan 19-27, 2012 Three peaks in local activity, two major (22-23rd and 26th)

55. ONC Folger Passage (Deep) data : ADCP vector currents

56. Stormy period: Jan 19-27, 2012 ADCP current vector data, daily averages, filtered North South East West

57. Stormy period: Jan 19-27, 2012 ADCP current vector data, daily averages, filtered North South East West Rapid wind shift Bottom return current Direction maintained, Speed dropped off

58. Stormy period: Jan 19-27, 2012 ADCP current vector data, daily averages, filtered North South East West Possible Barkley Sound outflow? Upper ~40m entrained during these events

59. ONC Folger Passage (Deep) data : Oxygen

60. Stormy period: Jan 19-27, 2012 Oxygen data at 94m

61. Stormy period: Jan 19-27, 2012 Oxygen data at 94m compared with ADCP vector currents

62. Stormy period: Jan 19-27, 2012 Oxygen data at 94m compared with ADCP vector currents Presumably return flow at depth draws from oxygenated upper flow Upwelling? (SE flow)

63. Summary - 2012 – surface forcing from Folger BPR: - more active and longer winter/spring - quiet mid-July/Aug, - Sept showed activity due to distant storms - Strong storm period in late Jan - Folger data show in general - very high resolution overview of wave activity - spectral tracks great for ID storm distance - depth of entrainment of surface water - indications of overturning flow due to storm-surge forcing/ interactions with Barkley Sound and bathy - resulting oxygenation at depth - short lived upwelling events ?

64. Analysis chart detail, Jan 22-23